<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        /* p {
            color: red;
        }
        
        .red {
            color: red;
        } */
        /* 每个选择器之间是紧挨着的不能有空格
        标签选择器必须在最前面 */

        p.red {
            color: red;
        }
    </style>
</head>

<body>
<!--
    需求:只让小可爱变红(不改变html结构)
 -->
<!-- 即是p又是class -->
<div class="red">小姐姐</div>
<p>小帅哥</p>
<p class="red">小可爱</p>
</body>

</html>